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Euphorbia guyoniana Boiss. & Reut. (Euphorbiaceae) is well known for the chemical diversity of its phytoconstituents, and toxicological properties that have been found in literature. However, research articles about their allelopathic characteristics are rarely reported. The current research study was conducted to explore phytochemical screening, allelopathic effects and their potential uses as natural herbicide of Euphorbia guyoniana Leaf extract, harvested from Oued Metlili, Algerian Sahara, on germination and seedling growth of four adventitious species (Bromus rubens L., Phalaris minor Retz., Plantago lagopus L., Ammi visnaga L.) and one cultivated species (Triticum durum L.) in laboratory conditions. The analyses of crude plant extract confirmed the flavonoids, anthocyanins, phenols and tannins, steroids, saponins, free quinone, sterols and triterpenes as well as carohydrates in the extract. Our results show that the leaf extract of Euphorbia guyoniana had significant allelopathic and bioherbicidal activity on germination and seedling growth of adventitious species and stimulatory activity on cultivated species at lower concentrations.

Background: Ticks are ectoparasites and can be vectors of a wide range of pathogens, posing significant health risks to livestock. In the Sahara Desert of Algeria, particularly among one-humped camels ( Camelus dromedarius ), there is a need to better understand the factors influencing tick infestation patterns to improve livestock management and health outcomes., Objectives: This study aimed to investigate the prevalence, intensity, and abundance of hard-bodied ticks (Acari: Ixodidae) among dromedaries, examining both intrinsic factors (sex, age, coat color) and extrinsic variables (farming systems, vegetation types, climate zones, and elevation) that might influence tick infestation in this region., Methods: Ticks were collected from 286 dromedaries across nine sites in the pre-Saharan regions of Algeria, with elevations ranging from 736 m to 980 m. The sampled camels, which ranged in age from 6 days to 21 years, were examined for tick infestations. The ticks were identified through macroscopic and microscopic methods, and their abundance was analyzed in relation to the camels' characteristics and environmental factors. Three breeding systems were recognized: extensive, intensive, and mixed., Results: A total of 980 ticks were collected, with Hyalomma dromedarii Koch, 1844 being the most abundant species (553 specimens), followed by Hyalomma impeltatum Schulze & Schlottke, 1930 (393 specimens), and Hyalomma excavatum Koch, 1844 (34 specimens). H. dromedarii showed a preference for parasitizing brown-coated dromedaries and exhibited significantly higher infestation levels during spring ( p  < 0.001). No significant association was observed between tick infestation and the camels' age or sex ( p  > 0.05). However, the farming system had a significant impact on tick abundance, with extensive and mixed systems showing higher tick burdens compared to intensive systems ( p  < 0.01). Additionally, the vegetation type, climate zone, and foraging habitat elevation were found to significantly influence tick densities and prevalence., Conclusion: This study provides essential insights into the tick infestation dynamics in dromedaries in drylands of Algeria. It highlights the influence of coat color, seasonality, and farming practices on tick burden, with brown-coated camels being more susceptible during the spring. The findings underline the importance of considering both intrinsic and extrinsic factors when developing effective tick control strategies, especially for camels raised in extensive or mixed farming systems in diverse arid rangelands. Future research should expand the scope to cover other arid regions in North Africa for a comprehensive understanding of tick-host dynamics., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2024 The Authors.)

Many cooked foods are prepared with spices and dried herbs; these can be contaminated by several types of microorganisms, including aerobic spore-forming bacteria. The Bacillus cereus group is very widespread in nature and is known among the common food contaminants. They are involved in food poisoning, causing two types of syndromes, diarrheal and emetic. The aims of the present work were to determine the prevalence of toxigenic Bacillus cereus spores in spices and herbs marketed in the Laghouat area and to identify their toxigenic genes via PCR. Among the 191 samples, 14.13% were determined to be B. cereus, with concentrations ranging from 2.52 to 5.82 log cfu/g, where the highest level of contamination was observed in allspice and ginger. Moreover, entFM (100%), nhe (88.23%) and cytK (70.58%) were the most frequently identified toxin genes, whereas hbl (23.52%) was less common, and no emetic toxin-encoding gene (cesB) was found in any of the samples. Considering the results of the present study, the B. cereus microbial load and toxin gene profiles of spices show that spices have potential for public health in Algeria. In this context, it is crucial to guarantee the microbiological safety of spices by respecting good hygiene practices, eliminating bacterial spores and toxin production via sterilization and using appropriate packaging for these products., (© 2024. The Author(s) under exclusive licence to Sociedade Brasileira de Microbiologia.)

Immunity and senescence play a crucial role in the functioning of the legume symbiotic nodules. The miss-regulation of one of these processes compromises the symbiosis leading to death of the endosymbiont and the arrest of the nodule functioning. The relationship between immunity and senescence has been extensively studied in plant organs where a synergistic response can be observed. However, the interplay between immunity and senescence in the symbiotic organ is poorly discussed in the literature and these phenomena are often mixed up. Recent studies revealed that the cooperation between immunity and senescence is not always observed in the nodule, suggesting complex interactions between these two processes within the symbiotic organ. Here, we discuss recent results on the interplay between immunity and senescence in the nodule and the specificities of this relationship during legume-rhizobium symbiosis., (Copyright © 2024. Published by Elsevier Inc.)

Bacterial resistance to different antimicrobial agents is growing with alarming speed, especially when bacterial cells are living in biofilm. Hybrid nanoparticles, synthesized through the green method, hold promise as a potential solution to this challenge. In this study, 66 actinomycete strains were isolated from three distinct marine sources: marine sediment, the algae Codium bursa , and the marine sponge Chondrosia reniformis . From the entirety of the isolated strains, one strain, S26, identified as Saccharopolyspora erythrea , was selected based on its taxonomic position and significant antimicrobial activity. Using the biomass of the selected marine Actinobacteria , the green synthesis of eco-friendly silver carbonate nanoparticles (BioAg 2 CO 3 NPs) is reported for the first time in this pioneering study. The BioAg 2 CO 3 NPs were characterized using different spectroscopic and microscopic analyses; the synthesized BioAg 2 CO 3 NPs primarily exhibit a triangular shape, with an approximate size of 100 nm. Biological activity evaluation indicated that the BioAg 2 CO 3 NPs exhibited good antimicrobial activity against all tested microorganisms and were able to remove 58% of the biofilm formed by the Klebsiella pneumoniae kp6 strain.

Traditional chemical synthesis, which involves the use of dangerous protocols, hazardous solvents, and toxic products and catalysts, is considered environmentally inappropriate and harmful to human health. Bearing in mind its numerous drawbacks, it has become crucial to substitute conventional chemistry with green chemistry which is safer, more ecofriendly and more effective in terms of time and selectivity. Elaborating synthetic protocols producing interesting new compounds using both microwave heating and heterogeneous non-toxic catalysts is acknowledged as a green approach that avoids many classical chemistry-related problems. In the current study, β-enaminones were used as precursors to the synthesis of modified 4-hydroxy-2-quinolone analogues. The synthesis was monitored in a benign way under microwave irradiation and was catalyzed by bismuth chloride III in an amount of 20 mol%. This method is privileged by using a non-corrosive, non-toxic, low-cost and available bismuth Lewis acid catalyst that has made it more respectful to the demands of green chemistry. The synthesized compounds were obtained in moderate to good yields (51-71%) and were characterized by 1 H, 13 C NMR, and IR spectroscopy as well as elemental analysis. Compound 5i was subjected to a complete structural elucidation using the X-ray diffraction method, and the results show the obtention of the enolic tautomeric form., Competing Interests: The authors declare that they have no competing interests., (This journal is © The Royal Society of Chemistry.)

Medicago (Medicago truncatula) establishes a symbiosis with the rhizobia Sinorhizobium sp, resulting in the formation of nodules where the bacteria fix atmospheric nitrogen. The loss of immunity repression or early senescence activation compromises symbiont survival and leads to the formation of nonfunctional nodules (fix-). Despite many studies exploring an overlap between immunity and senescence responses outside the nodule context, the relationship between these processes in the nodule remains poorly understood. To investigate this phenomenon, we selected and characterized three Medicago mutants developing fix- nodules and showing senescence responses. Analysis of specific defense (PATHOGENESIS-RELATED PROTEIN) or senescence (CYSTEINE PROTEASE) marker expression demonstrated that senescence and immunity seem to be antagonistic in fix- nodules. The growth of senescence mutants on non-sterile (sand/perlite) substrate instead of sterile in vitro conditions decreased nodule senescence and enhanced defense, indicating that environment can affect the immunity/senescence balance. The application of wounding stress on wild-type (WT) fix+ nodules led to the death of intracellular rhizobia and associated with co-stimulation of defense and senescence markers, indicating that in fix+ nodules the relationship between the two processes switches from opposite to synergistic to control symbiont survival during response to the stress. Our data show that the immune response in stressed WT nodules is linked to the repression of DEFECTIVE IN NITROGEN FIXATION 2 (DNF2), Symbiotic CYSTEINE-RICH RECEPTOR-LIKE KINASE (SymCRK), and REGULATOR OF SYMBIOSOME DIFFERENTIATION (RSD), key genes involved in symbiotic immunity suppression. This study provides insight to understand the links between senescence and immunity in Medicago nodules., (© American Society of Plant Biologists 2022. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

The polyphenol oxidase was extracted and purified from truffles (Terfezia arenaria) and it exhibited a molecular weight of 67 kDa. The truffle PPO was able to oxidize monophenolic, o-diphenolic and triphenolic substrates. Thus, the enzyme seems to be stable under wide range of pH and temperature. Best catalytic efficiency was observed for catechol as substrate (Kcat/km; 674.2 S -1  mM -1 ).The effect of detergents, chaotropic agents, metal ions and eleven different inhibitors on relative activity of Truffles PPO was also investigated. A latent form of enzyme was observed and its activity was stimulated using 4 mM of SDS. Likewise, the type of inhibition and the values of K I and IC 50 were reported for L-cysteine, Sodium fluoride, sodium metabisulfite and kojic acid. Besides, the effect of four concentrations of kojic acid(0.05.,0.1.,0.2 and 0.3 mM) on thermal inactivation of PPO was performed in temperature range " 60-75° C". The use of Kojic acid increase the rate of inactivation process and disrupt enzymatic activity. Moreover, the combined effect of temperature and kojic acid prevent from enzymatic browning reaction and maintain high antioxidant activities including ABTS scavenging activity, FRAP, and total phenolic contents., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Catechol oxidase (PPO) was extracted and purified from Tadela (Phoenix dactylifera L.) date fruit, by a procedure that included (NH 4 ) 2 SO 4 precipitation followed by dialysis, Q-Sepharose bb ion-exchange chromatography and HPLC gel filtration chromatography. Some of its biochemical characteristics were studied. The purification rate and the yield were 80% and 20%, respectively. The Tadela date fruit catechol oxidase exhibited a molecular weight of 90 kDa using SDS-PAGE. The catechol oxidase showed only o‑diphenolase and triphenolase activities while no monophenolase activity was detected. A better affinity was observed using catechol as substrate (Km = 35 mM) with thus, a higher Vmax/Km ratio (80 U/mM·mL). This enzyme is thermostable in the temperature range (30-60 °C) with optimum activity in acidic range of pH. Four inhibitors were used for the control of enzymatic browning, of which sodium metabisulfite was the most potent (IC 50  = 0, 11 mM). The values of K I and mechanism of inhibition were also determined. No significant change on enzyme activity was noticed in the presence of metal ion and detergents. Therefore, thermal inactivation was studied in the temperature range between 60 and 80 °C using catechol as substrate. Their kinetic (K, D, t 1/2 , Zt, Ea) and thermodynamic (ΔH, ΔG and ΔS) parameters were also estimated., (Copyright © 2018 Elsevier B.V. All rights reserved.)